The oedemerid species Oedemera sexualis Marseul, 1877 is reported for the first time from Korea. The genus Oedemera Olivier, 1789, within subfamily Oedemerinae and family Oedemeridae, is one of the common oedemerid beetles being widely distributed throughout the world. The world-widespread genus Oedemera is presented 3 subgenera and 104 species in Palaearctic region. Until now, 8 species and subspecies were recorded in Korea. O. sexualis was found in Is. Yongcho and Is. Bijin in Tongyeong-si, Gyeongsangnamdo of Korea, bringing the number of Korean Oedemera species to 9 species. In this study, we report the taxonomic key to the genus Oedemera of Korea, and morphological description of O. sexualis.